Patent GB-387323-A (GB)
Title: Process of polymerizing vinyl compounds
IPC: C08F4/28
Filed: 1931-04-27
Abstract: Vinyl compounds are polymerized by heating them in the presence of a catalyst which is the reaction product of an aliphatic organic acid anhydride with hydrogen peroxide, sodium peroxide, or a true per salt (i.e. one which yields hydrogen peroxide on hydrolysis with water), the process being carried out in the absence of non-catalytic bye-products of the reaction by utilizing the catalyst in the form of a solution in a solvent in which the non-catalytic bye-products are insoluble (which solvent may itself be a vinyl compound, e.g. vinyl acetate).  Particularly suitable as catalyst is the product of reaction of acetic anhydride and sodium perborate, the preparation of which is carried out according to the process of Specification 387,335.  The process may be conducted in the presence of a diluent additional to that in which the catalyst is dissolved, and may be carried out in a continuous manner by drawing off a portion of the reaction products and adding a substantially corresponding amount of reagents.  When polymerizing vinyl acetate, the process may be carried out under a reflux condenser at a temperature not above 75 DEG  C., preferably about 70 DEG  C., the reaction being cooled by the influx of cool condensate from the condenser.  In order to prevent p  local heating it is advantageous to add a solvent, such as toluene, benzene or alcohol, preheated to about 70 DEG  C., either all at the beginning of the reaction or at a suitable rate after the thickening of the solution has reached a certain point, e.g. at such a rate that the viscosity remains constant, as determined, for instance, by the speed of a stirring device under constant power input.  Polymerization may be effected below 70 DEG  C. but at a slower rate, or at higher temperatures, e.g. about 100 DEG  C., by working in a bomb or closed autoclave.  In examples: (1) vinyl acetate free from acetaldehyde is refluxed at 70 DEG  C. with the product of example (1) of Specification 387,335; (2) vinyl acetate free from acetaldehyde is refluxed with the product of example (2) of Specification 387,335; (3) vinyl acetate to which acetaldehyde has been added is refluxed with the product of example (3) of Specification 387,335; the product is an excellent substitute for chicle; (4) the process of (1) is carried out with the addition of toluene as diluent; (5) the reaction mixture of (1) is refluxed at 70 DEG  C. until it has attained about the consistency of glycerine, and a solvent such as toluene, heated to 70 DEG  C. is added at such a rate as to keep the viscosity approximately constant, the temperature being raised during the latter part of the process. Other vinyl compounds specified as starting materials are: other vinyl esters, e.g. vinyl butyrate and propionate, vinyl halides, particularly vinyl chloride, and mixtures of vinyl esters and vinyl halides.  Other compounds suitable for the preparation of the catalysts include on the one hand sodium percarbonate, sodium peroxide and hydrogen peroxide, and on the other hand propionic anhydride.  Specifications 15271/14, 261,406, 280,246, and 295,322, [all in Class 2 (iii), Dyes &c.], also are referred to.  The Specification as open to inspection under Sect. 91 comprises also the polymerization of vinyl compounds by means of catalysts prepared by the reaction of an organic acid anhydride with hydrogen peroxide, sodium peroxide, or a true per salt in the absence of a solvent and without removing the non-catalytic bye-products.  In examples, acetic anhydride and sodium perborate are (a) added directly to the vinyl compound, or (b) warmed together and then added.  This subject-matter does not appear in the Specification as accepted.ALSO:As catalysts for the polymerization of vinyl compounds are employed reaction products of an aliphatic organic acid anhydride with hydrogen peroxide, sodium peroxide, or a true per salt (i.e. one which yields hydrogen peroxide on hydrolysis with water) in the form of a solution in a solvent in which the non-catalytic bye-products of the reaction are insoluble (which solvent may itself be a vinyl compound, e.g. vinyl acetate).  Particularly suitable is the product of reaction of acetic anhydride and sodium perborate, prepared as described in Specification 387,335.  Other compounds suitable for the preparation of the catalysts are on the one hand sodium percarborate, sodium peroxide and hydrogen peroxide, and on the other hand propionic anhydride. Specifications 15271/14, 261,406, 280,246, and 295,322, [all in Class 2 (iii), Dyes &c.], are referred to.  The Specification as open to inspection under Sect. 91 comprises also the preparation of the catalysts by the reaction of an organic anhydride with hydrogen peroxide, sodium peroxide, or a true per salt in the absence of a solvent and without removing the non-catalytic bye-products.  In examples, acetic anhydride and sodium perborate are (a) added directly to the vinyl compound, or (b) warmed together and then added.  This subject-matter does not appear in the Specification as accepted.